Adjustable control switch



March 22, 1938. M HENMNG 2,111,856

ADJUSTABLE CONTROL SWITCH Filed Oct. 3, 1932 2 Sheets-Sheet 1 J/VMW/a/ when (Jflnymwh Mal-ch22, 1938. E. HENNiNG 2,111,856

ADJUSTABLE CONTROL SWITCH Filed Oct. 3, 1932 2 Sheets-Sheei 2 Iii Patented Mar. 22,1938

UNITED Tff osslcs The object of my invention is to provide adjustable control switch which is simple, durable and comparatively inexpensive to manufacture.

A further object is to provide an adjustable- 5 control switch having a control knob which be manipulated for range adjustment, for oojust= merit of the switch structure to on on positions manually and for manual reset oi the switch structure after it has been tmpped 10 overload circuit, the controlswitch having aeldl= tional range and diflerential adjusting meshe hism which are accessible through the control knob and time from the outside oi? switch casing without removing the knob, the knob 1 serving as an indicator of the position oi the switch.

Still a further object is to provide an adjust= able control switch especially adapted tor con= trol of a mechanical refrigerator with a single 25 control knob for effecting cold control, time ing the switch for defrosting, it on for starting automatic operation either after it has been turned 01! fordefrosting or after it has been tripped because of an overload, diiler= 25 ential adjusting and additional range ailiustino being eflected through an opening in the knob itself so that the switch casing does not have to be removed or opened for any of the adjust= ing operations.

' Still a further object is to provide a control mechanism which moves the switch to open circuit position, the latch being also manually releasable whereby the thermally releasable catch can remain in its caught position when the switch is manually operated to open circuit position.

Still a further object is to provide specific simplified details of construction in the control switch which will appear in the following specification.

With these and other objects in view my inventionj consists in the construction, arrangenient and combination of the various parts of my device, whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed 50 out in my claims, and illustrated in the accompanying drawings, in which: 7 Figure l is a side elevation of an adjustable control switch embodying my invention and showing a cover plateremoved therefrom.

55 Flgure2isasimilarview withpartsoi the (or coo: o

structure; and

J range o'rljwting mechanism in cross a I 3 a sectional View on the line M or I aseotionol View on the l l a a View to the right halt oz? cew of the sectioned.

- sectional View on the line o oi? J the manuahj released i. View on the li ll oi "f-v than o latched position. I

9 a sectional View on the line o e oi 5 how parts of the switch may iii is amend elevation in the direction of the ow i 0 adjacent If.

1S a separated perspective view of control 9 oi the switch assembly.

Figure L is sectional view on the line 82- 412 7 of Figure 4 Figure seotionm View on the line ti id of Figure 1c.

Figure it p. elevation of t e switch vIligure 155 is a sectional view on the line l5-==l8 of 2.

On the accompanying drawings, I have used the reference numeral so to indicate generally a switch casing. The casing in has a front plate i2 and a cover plate ii. The cover plate I4 is held in position by a screw l6 (see Figure 6).

Within the switch casing I0, I provide an L- shaped bracket A for supporting various movable parts of the switch mechanism. The bracket A is confined in position by its ends being positioned in slots 88 and 20 and a." clip 22 engaging the central portion of the bracket. The clip 22 is held in position by a screw 2|.

The bracket A carries a pin 26 on which a pressure operated element B is pivoted. The element B is adapted to be moved in one direction by pressure within a bellows 28, such pressure being caused by a temperature increase when the switch is used for controlling a mechanical refrigerator.

The bellows 28 has a connection 30 with which a tube and bulb (not shown) may be connected and the tube, bulb and bellows may be suitably charged in the ordinary manner so that when the bulb is located within a refrigerating oomm" similar to 6 showmg l5 partment, the bellows 28 will be expanded by a rise of the temperature therein.

Through the medium of a cap 32, the bellows 28 is connected by an engagement type of connection with the pressure operated element B. The cap 32 carries a pin 34 adapted to engage in a depression 38 of the element B.

The bellows 28 is opposed by a spring 38. The spring 38 has one end seated in a cup 40 which has projections 42 adapted to engage in notches 44 of the element B. Thus the cup is pivoted relative to the element. The other end of the spring 38 is seated in a cup 40 which is screwthreaded on a rotatable adjusting sleeve 48. The cup 48 is held against rotation by a forked arm 48a (see Figure 12) engaging a rib 46b of the casing I0.

The sleeve 48 is adapted to be rotated by a control knob 50. The control knob 50 has an indicator disk 52 secured thereto by screws 54. A release disk 58 is also secured thereto by the screws.

A sleeve 58 extends rotatably through the front plate I2 of the casing I0. The sleeve 58 has flattened surfaces 58a, as shown in Figure 15 and the disk 52, as well as the knob 50 have bores which are of the same cross section so that the knob 50 is slidable relative to the sleeve 58 but non-rotatable relative thereto. Thus rotation of the knob will rotate the sleeve.

Rotation of the sleeve 58 is imparted to the sleeve 48 by a non-circular socket of the sleeve 88 receiving a similarly shaped flange SI of the sleeve 48 (see Figure 12).

Thus far, the pressure operated element B, the range of which can be adjusted by rotating the knob 50, has been described. The element B is for operating a switch which will now be described.

A socket 82 is formed in the casing I0 (see Figures 7 and 10). Prongs 64 and 86 extend from the easing into the socket. The prong 84 has an :xtension 64b terminating at a screw 88 (see Figure 1). A resistance coil I0 is connected therewith and with a screw I2. The screw I2 is carried by a bracket I4 which terminates at its opposite end in a contact I8. The prong 88 has a contact I8 and terminates at a screw or the like 80 which holds the prong in position.

The bracket I4 (see Figure 7) has arms 14a through which a switch element C is slidable. The switch element C is preferably made of insulating material and constrained to the closed circuit position by a spring 82. It is provided with an opening 84 into which a snap acting arm D, or more specifically a lip 88 thereof. extends.

The switch element C carries a pair of bridging contacts 88. These are carried on a bar pivoted at 80. A spring 82 is interposed between the switch element C and the bar for aiding in a quick opening of the switch contacts, the pivot 80' somewhat loosely connecting the element 0 with the bar for this purpose.

The snap acting lever D is pivoted in depressions 84 formed in the bracket A. It is adapted to be snapped from one position to another by a spring 88 having heads 88 engaging pointed elements I00 of the bracket A and of the pressure operated element B.

The motion of the lever D to open circuit position is arrested by a shoulder I02 oi the switch element C engaging the left extension 14a of the bracket I4 in Figure '7. Its motion in the opposite direction is arrested by an extension I04 of the lever D engaging a differential adjusting screw I08. The screw I08, as shown in Figure 2, is carried by and threaded relative to the sleeve 48 so that rotation of the screw will adjust it longitudinally relative to the sleeve. This provides a differential adjustment inasmuch as the extension I04. can be stopped at different positions, thereby requiring more or less reduction of pressure in the bellows 28 to start the lever D toward its switch opening position.

From the foregoing description, it will be obvious that I have provided a switch construction in which normal range adjustment may be eifectcd by rotation of the knob 50. The knob 80 is limited in its rotation by a stop pin I08 in the sleeve 58 (see Figure 9) engaging a stop screw IIO carried by the casing I0. Additional range adjustment may be had by removing a closure screw H2 in the knob 50 and inserting a screw driver or the like H4 whereupon the screw I08 can be engaged for pressing the sleeve 48 inward against the action of the spring 38 to the position shown in Figure 9.

As shown in Figure 14, it will be noted that the .front wall I2 oi the casing I0 has graduations thereon. The arrow shown on the knob 50 can be adjusted any number of points above zero before the parts are moved to the position of Figure 9 and then after they are moved to this position, it can be moved back to zero and the screw driver II4 thereafter withdrawn whereupon the sleeve 48 will again assume a connected position with respect to the sleeve 58, but the range will have been additionally changed to the extent of the number of graduations over which the knob was rotated after placing the parts in the position of Figure 9. Thereafter, the high and low limits of the normal range adjustment as caused by rotation of the knob 50 will be changed by this means of additional range adjustment.

The differential adjustment is effected by rotating the screw I08 by the screw driver II 4 inserted as shown in Figure 9. After additional range adjustment and/or differential adjustment has ben effected, the screw driver is removed and the screw I I2 replaced. It is thus obvious that the mechanism for the two adjustments just mentioned is accessible through the knob 60 without removing it or without opening the casing I0.

It is desirable also to have the knob 80 manually operable for turning the switch "on" and off and manually operable for resetting the switch after it has been opened because of an overload condition.

The mechanism for opening 01 the switch because of overload will now be described. A slide member E is connected with the bracket A by a shouldered screw II8 extending through a slot H8 01' the slide member. The slide member has a U-shaped hook I20 to engage the disk 88 of the knob 80 so that the slide member can be pushed or pulled as desired by manipulating the knob.

A thermally releasable catch F and a latch G are slidable in the bracket A, arms I22 and I24 thereof respectively being slidable through slots around the pivot pin 28, their general shape being shown perhaps best by dotted lines in Figure 1. The catch member F is provided with a catch lug the twitch element to move t 0 to such petition tote l3! adapted to engage a ratchet Wheel shown in Figures 2 and 4; The ratchet Wheel 036%, soldered to a tube I38 which in. tum is suooorteel on a pin Mt. The coil of resist-moo who it w rounds the tube t 38 so that upon an excessive how of current through the coil, the comet wlil he melted so that the ratchet wheel 36 he Th teterl. by the catch fltt and the cotch her i which rotation will he caused h" the c te use.

The lotchmemhet G is adopted m assume the position oi Figure who em shoulotet= t thereof engages the edge the wt in e; flange wt of the hatchet l Somme E132 has a, tendency to totote ,G counterclockwise as viewed lit the extension flt t thtoug'h the o the as a otvot. Thus the spring 582 to the leteh show-tier M2 to. latched too Whom the catch tilt howevet -meltlng of the solder connection ratchet wheel [1536 thetuhe 188, of the member engages member tot swinging the memhes from the Figure t oostttoh, Th me vthem he oueheel toward the he of Figure 6 due to the action oi This may he termed the uhlat to the position for opening the etch 7 It will he noted that the memher L (IE2 canted there-lot, This em"; and t) is to engage eh when an overload con ent flows 0 degree of overload loathe oletext of the wire useol he the tesiste whereby the heat rethetetl thereh to the cumeht fiotmtg through I gozeoletemaihed.

The latch of the member uiotetched from the opening 96G. iolishetl by pulling om hhoh EC l the slide memh has an which is positioned to o slot t 58 ltommlly the slide E position of 121 v the 05G engages the left end e; 6% Within lmoh 0 ton circuit oosltloh, Thus the tl' e tholtne of the lug 15B he? downwardly so as to L shoulder 6 32 from edge of resulting he the member (6 heihg move open cltoutt posittou of FLJUIQ 63 due he ot' the spring 132. Thus mantel controt circuit to open position tsefiecte l have been determine the H62 to were on tnteezcol part of the letoh Zlttvill he noted, however, that to peyote thereto. It has o lug W3 21-h edge of the latch memhet G to h otel move= meet of the em ltlt to one olh ttt is provided on the arm which m. spring engages whereby to the stop lug ltt engaged with the efige of the G well as import sliding motion to memher pivotal motion to it tending to retain lotcheol es hereinhei'ore desctlbed.

The purpose of pivoting the [152 is so that when the parts are moved to the toll lm .tecte l6 and "US during; latching or retet manually or thermally, the left end of the lug hit in Ftgure ll will engage an edge t52o of the mm [152 to swing the arm counterclockwise from the position shown in Mem 1. This the arm engage the extensioh G of the switch elemeht (C to hol-zl the contacts t separated from the co "on" This @ldGf. to prevent mohuoey mg the switch oloseel position the he tesetting; ooetotioh has been 322% e hmoh 5t eieaseel whereupontt hr outwsmcl the position of do will move to the $19!) and the line e a of 8, thereby pemutti 5' he s e soliel'l'me posttioh tter interfere itch ete and closet 1oe Roms.

it anal 3, a slot 868 com-- '0 that does no ther Toy clrculal' loot-sessions cl WH] 3N noted, ere and respectively.

i k em "a s3 iet 02. This sttuetthe in W es 9, mumher the knob we. cater VLL oce Wm t The mantle-Hy to of; position there is no wear on the of the ratchet [136. The latch shoulder [N32 to of much more rugged cohttt'ucttoh the hatchet Wheel [I86 and thus takes the manual tmletchmg rathetthen letting ell wears come on the teeth which are in my o otruetiom used only for thermal uhletchlng o resetting thereafter.

The lmoh tt oleo serves eh tnofltcotor the e lo ttlopetl to oh position due to overload current flowing therethrough. When the solder melts and thereby permits the ratchet wheel I36 to rotate, the member F, or more specifically a lug Ia thereof, (see Figures 6 and 11) moves toward the right and engages an extension IZBa of the member E to move it from the dotted line position of Figure 8 to the full line position of Figure 6. This causes the knob 50 to be moved to the position of Figure 5 where the indicating disk 52 will be observable beyond the end of a hub in in which the disk 52 is normally concealed.

Although I have illustrated a specific control, changes may be made in the construction and arrangement of the parts of my device without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims, any modified forms of structure or use of mechanical equivalents, which may be reasonably included within their scope.

I claim as my invention:

1. In an adjustable control switch, a pressure operated element, a snap acting element asociated therewith for operation thereby, a switch element operated by said snap acting element, resilient means opposing said pressure operated element and means for adjusting said resilient means comprising a rotatable element for changing the adjustment upon rotation thereof, a knob element for rotating said rotatable element, means for 1 I preventing removal 01 said knob and means of operative connection between said knob element and said rotatable element, said means of operative connection comprising a non-circular socket in one of said elements and a similarly shaped portion on the other element to fit therein, said socket and said portion being disassociable against the action of said resilient means while said means for preventing removal of said knob remains operative.

2. In an adjustable control switch, a pressure operated element, a switch element operable thereby to make and break an electric circuit, spring means opposing said pressure operated element, a range adjusting element for changing the tension of said spring means, overload means also operable to break said electric circuit, said overload means comprising a thermally responsive member and a releasable catch which is released upon the thermally responsive member operating and a latch releasable by said catch engaging therewith after such operation, said latch being operable to break said circuit, said range adjusting element being operatively connected with said latch to manually release it.

3. In an adjustable control switch, a pressure operated element, a switch element operable thereby to make and break an electric circuit, spring means opposing said pressure operated element, a range adjusting element for changing the tension of said spring means, overload means also operable to break said electric circuit, said overload means comprising a thermally responsive member and a releasable catch which is released upon the thermally responsive member operating anda latch releasable by said catch engaging therewith after such operation, said latch being operable to break said circuit, said range adjusting element being operatively connected with said latch to manually release it and to reset it after either overload or manual release.

4. In an adjustable control switch, a pressure operated element, a switch element operable thereby to make and break an electric circuit, spring means opposing said pressure operated element, a range adjusting element for changing the tension of said spring means, overload means also operable to break said electric circuit, said overload means comprising a thermally responsive member and a releasable catch which is released upon the thermally responsive member operating a latch releasable by said catch engaging therewith after such operation, said latch being operable to break saidcircuit, said range adjusting element being operatively connected with said latch for movement thereby to a different position after said latch becomes unlatched and means on said range adjusting element to indicate such different position.

MALCOLM E. HENNING. 

